Print selection is greyed out printing part of web page

It's possible that some selections are not detected when you call up the Print dialog (e.g., by pressing Ctrl+p). For example, text in editing controls (like this box I'm typing in now) is not detected as a selection. Possibly selected text in an embedded document (inline frame) might not be detected. In the case of an iframe, when you right-click your selected text, there will be a "This Frame" item on the menu. If you expand that part of the menu, there may be a Print command that lets you print the selection. (I don't have a page handy to test with...)